VIGNA UNGUICULATA (L).WALP BY AZOTOBACTER SP. INDOLE-3-ACETIC ACID PRODUCTION AND ENHANCED PLANT GROWTH PROMOTION OF

In the present study the rhizosphere soil sample was collected from different cultivation lands in and around Gandhigram Rural Institute- Deemed University, Gandhigram, Dindigul, Tamilnadu, India. Then the Azotobacter sp. Was isolated and identified using standard procedures. The Azotobacter sp. Was screened for Indole acetic acid production and standardized for IAA production at different tryptophan concentration i.e 1-5 mg/ml and control (without Tryptophan). The results showed that the Azotobacter sp. Significantly produce higher quantity of IAA (52.80 mg/ml) at 5 mg/ml of tryptophan concentration on fifteenth day compared with others. A low amount (7.48 mg/ml) of IAA production was recorded by Azotobacter sp. In control (without tryptophan addition). The plant growth studies using Azotobacter sp. At different concentration (0-5 ml) using vigna unguiculata (L).walp at different day intervals (5 and 10 days) were done. At tenth day the germination percentage (80%), Root length (12.03±0.63), Shoot length(24.68±0.43), fresh weight of whole plant(3.59±0.06) and dry weight of whole plant(0.49±0.39) were significantly enhanced by the Azotobacter sp. at 5ml concentration on tenth day compared to other concentration and control.